Power storage device, lid unit

Abstract

This power storage device comprises an electrode body and an exterior body which seals the electrode body. The exterior body includes an exterior film wrapping the electrode body, a lid body sealing the electrode body together with the exterior film, and a first sealing portion being a portion where the exterior film is closed. The power storage device is provided with at least one of a check valve and an unsealing valve in the first sealing portion.

Description

[Technical field]

[0001] The present invention relates to an electricity storage device and a lid unit. [Background technology]

[0002] Patent Document 1 discloses an example of an electricity storage device. This electricity storage device includes an electrode body and an exterior body that seals the electrode body. The exterior body includes an exterior film that wraps the electrode body so that an opening is formed, and a lid body that is placed on the opening. The exterior film and the lid body are joined together. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-123686 Summary of the Invention [Problem to be solved by the invention]

[0004] When the electricity storage device is a lithium ion battery, for example, gas may be generated due to volatilization of an organic solvent in the electrolyte, and the internal pressure of the exterior body may increase. No consideration has been given to discharging the gas generated inside the exterior body to the outside of the electricity storage device.

[0005] An object of the present invention is to provide an electricity storage device capable of discharging gas generated inside an exterior body, and a lid unit used for this electricity storage device. [Means for solving the problem]

[0006] An energy storage device according to a first aspect of the present invention is an energy storage device comprising an electrode body and an exterior body that seals the electrode body, wherein the exterior body includes an exterior film that wraps the electrode body, a lid that seals the electrode body together with the exterior film, and a first sealing portion that is a portion where the exterior film is closed, and the energy storage device comprises at least one of a check valve and an opening valve that are arranged in the first sealing portion.

[0007] An energy storage device according to a second aspect of the present invention is the energy storage device according to the first aspect, wherein the first sealed portion is a portion sealed by bonding the mutually facing inner surfaces of the exterior film, or a portion sealed by bonding the outermost layer and the innermost layer of the exterior film.

[0008] An energy storage device according to a third aspect of the present invention is an energy storage device comprising an electrode body and an exterior body that seals the electrode body, wherein the exterior body includes an exterior film that wraps the electrode body, a lid body that seals the electrode body together with the exterior film, and a second sealing portion in which the lid body and the exterior film are joined, and the energy storage device comprises at least one of a check valve and an opening valve that are arranged in the second sealing portion.

[0009] An electricity storage device according to a fourth aspect of the present invention is the electricity storage device according to the third aspect, wherein the lid body has a recess formed on a side surface, and at least one of the check valve and the opening valve is disposed in the recess.

[0010] An energy storage device according to a fifth aspect of the present invention is the energy storage device according to the third or fourth aspect, wherein the energy storage device includes the check valve, the exterior body includes at least two of the lid bodies, and the opening pressure of the check valve arranged in the second sealing portion corresponding to one of the lid bodies is lower than the opening pressure of the check valve arranged in the second sealing portion corresponding to the other of the lid bodies.

[0011] An electricity storage device according to a sixth aspect of the present invention is the electricity storage device according to the third or fourth aspect, wherein the electricity storage device comprises the opening valve, the outer casing comprises at least two of the lid bodies, and the opening pressure of the opening valve arranged in the second sealing portion corresponding to one of the lid bodies is lower than the opening pressure of the opening valve arranged in the second sealing portion corresponding to the other of the lid bodies.

[0012] The seventh aspect of the present invention is an energy storage device according to the third or fourth aspect, wherein the outer casing has at least two lid bodies, and at least one of the check valve and the opening valve is arranged in the second sealing portion corresponding to one of the lid bodies, and neither the check valve nor the opening valve is arranged in the second sealing portion corresponding to the other lid body.

[0013] An energy storage device according to an eighth aspect of the present invention is an energy storage device comprising an electrode body and an exterior body that seals the electrode body, the exterior body including an exterior film that wraps the electrode body and a lid that seals the electrode body together with the exterior film, and the energy storage device comprises a check valve attached to the lid.

[0014] A ninth aspect of the present invention is an energy storage device according to the eighth aspect, wherein the exterior body includes at least two lid bodies, and the opening pressure of the check valve attached to one of the lid bodies is lower than the opening pressure of the check valve attached to the other lid body.

[0015] An energy storage device according to a tenth aspect of the present invention is the energy storage device according to the eighth aspect, wherein the exterior body has at least two lid bodies, one of the lid bodies is equipped with the check valve, and the other of the lid bodies is not equipped with the check valve.

[0016] An electricity storage device according to an eleventh aspect of the present invention is an electricity storage device comprising an electrode body and an exterior body that seals the electrode body, the exterior body including an exterior film that wraps the electrode body and a lid body that seals the electrode body together with the exterior film, the electricity storage device comprising an opening valve attached to the lid body.

[0017] The energy storage device according to a twelfth aspect of the present invention is the energy storage device according to the eleventh aspect, wherein the outer casing has at least two lid bodies, and the opening pressure of the opening valve attached to one of the lid bodies is lower than the opening pressure of the opening valve attached to the other lid body.

[0018] An energy storage device according to a thirteenth aspect of the present invention is the energy storage device according to the eleventh aspect, wherein the outer casing has at least two lid bodies, one of the lid bodies is equipped with the opening valve, and the other of the lid bodies is not equipped with the opening valve.

[0019] The electricity storage device according to a fourteenth aspect of the present invention is an electricity storage device comprising an electrode body and an exterior body that seals the electrode body, the exterior body including an exterior film that wraps the electrode body and a lid that seals the electrode body together with the exterior film, and the electricity storage device comprises at least one of a check valve and an opening valve that are attached in a position that allows gas generated inside the exterior body to be discharged.

[0020] A power storage device according to a fifteenth aspect of the present invention is the power storage device according to the fourteenth aspect, further comprising the check valve and the opening valve, wherein the opening pressure of the check valve is lower than the opening pressure of the opening valve.

[0021] A lid unit according to a sixteenth aspect of the present invention comprises a lid body used as an exterior body for sealing an electrode body, and at least one of a check valve and an opening valve attached to the lid body. Effect of the Invention

[0022] According to the electricity storage device of the present invention and the lid unit used in this electricity storage device, gas generated inside the exterior body can be discharged. [Brief description of the drawings]

[0023] [Figure 1A] FIG. 1 is a perspective view illustrating an electricity accumulation device according to a first embodiment. [Figure 1B] 1B is a diagram showing a method for measuring the seal strength of a second sealing portion of the electricity storage device in FIG. 1A. [Diagram 2] 1B is a cross-sectional view showing an example of a layer structure of an exterior film included in the electricity storage device of FIG. 1A. [Diagram 3] FIG. 1B is a diagram showing the state in which the exterior film of the power storage device of FIG. 1A is unfolded. [Figure 4] 1B is a perspective view of a lid provided in the electricity storage device of FIG. 1A. [Diagram 5] FIG. 1B is a front view of a check valve included in the electricity storage device of FIG. 1A. [Figure 6] 4 is a flowchart showing an example of a method for manufacturing the electricity storage device in FIG. 1A. [Figure 7] FIG. 11 is a perspective view illustrating an electricity accumulation device according to a second embodiment. [Figure 8] Cross-sectional view taken along line D8-D8 in Figure 7. [Figure 9] FIG. 13 is a perspective view illustrating an electricity accumulation device according to a third embodiment. [Figure 10] 10 is a cross-sectional view showing an example of a layer structure of an exterior film included in the electricity storage device of FIG. 9. [Figure 11] FIG. 13 is a perspective view illustrating an electricity accumulation device according to a fourth embodiment. [Figure 12] FIG. 4 is a cross-sectional view of an electricity accumulation device according to a modified example of the first embodiment. [Figure 13] FIG. 13 is a front view of an electricity accumulation device according to a modified example of the second embodiment. [Figure 14] FIG. 14 is a front view of a lid provided in the electricity storage device of FIG. [Figure 15] FIG. 13 is a front view of an electricity accumulation device according to another modified example of the second embodiment. [Figure 16] FIG. 16 is a front view of a lid provided in the electricity storage device of FIG. [Figure 17] 13 is a cross-sectional view showing another example of the arrangement of the opening valve included in the electricity accumulation device of the fourth embodiment. FIG. [Figure 18] FIG. 13 is a perspective view of an electricity accumulation device which is a modified example of the electricity accumulation device according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, an electricity storage device according to one embodiment of the present invention will be described with reference to the drawings. In this specification, a numerical range indicated by "to" means "not less than" or "not more than." For example, the expression "2 to 15 mm" means 2 mm or more and 15 mm or less.

[0025] [1. First embodiment] <1-1. Configuration of the power storage device> FIG. 1A is a plan view that shows a schematic diagram of an electricity storage device 10 of a first embodiment. FIG. 1B relates to a method for measuring the seal strength of a second sealing portion 80 of the electricity storage device 10. FIG. 2 is a cross-sectional view showing a layer structure of an exterior film 50 included in the electricity storage device 10 of FIG. 1A. FIG. 3 is a diagram showing a state in which the exterior film 50 included in the electricity storage device 10 of FIG. 1A is unfolded. FIG. 4 is a perspective view of a lid body 60 included in the electricity storage device 10 of FIG. 1A. FIG. 5 is a front view of a check valve 90 included in the electricity storage device 10 of FIG. 1A. In FIG. 1A, the direction of the arrow UD indicates the thickness direction of the electricity storage device 10, the direction of the arrow LR indicates the width direction of the electricity storage device 10, and the direction of the arrow FB indicates the depth direction of the electricity storage device 10. The directions indicated by the arrows UDLRFB are common to the following figures.

[0026] The power storage device 10 includes an electrode body 20, an electrode terminal 30, and an exterior body 40. The electrode body 20 includes electrodes (positive and negative electrodes) constituting a power storage member such as a lithium ion battery, a capacitor, an all-solid-state battery, a semi-solid battery, a quasi-solid battery, a polymer battery, an all-resin battery, a lead-acid battery, a nickel-metal hydride battery, a nickel-cadmium battery, a nickel-iron battery, a nickel-zinc battery, a silver oxide-zinc battery, a metal-air battery, a polyvalent cation battery, or a capacitor, and a separator. In this embodiment, the shape of the electrode body 20 is an approximately rectangular parallelepiped. Note that the term "approximately rectangular parallelepiped" includes, in addition to a complete rectangular parallelepiped, a solid body that can be regarded as a rectangular parallelepiped by modifying the shape of a part of the outer surface, for example. The shape of the electrode body 20 may be, for example, a cylinder or a polygonal prism.

[0027] In this embodiment, the power storage device 10 includes two electrode terminals 30. The electrode terminals 30 are metal terminals used for inputting and outputting electric power in the electrode body 20. One end of the electrode terminal 30 is electrically connected to an electrode (positive electrode or negative electrode) included in the electrode body 20. The other end of the electrode terminal 30 protrudes outward from an edge of the exterior body 40, for example. Note that the electrode terminal 30 may not protrude from the exterior body 40, for example, as long as it is capable of inputting and outputting electric power to and from the electrode body 20. When the cover body 60 described later is made of, for example, a metal, the cover body 60 may also function as the electrode terminal 30. In this case, the cover body 60 having the function as an electrode terminal may or may not protrude from the exterior body 40.

[0028] The metal material constituting the electrode terminal 30 is, for example, aluminum, nickel, copper, etc. For example, when the electrode body 20 is a lithium ion battery, the electrode terminal 30 connected to the positive electrode is usually made of aluminum, etc., and the electrode terminal 30 connected to the negative electrode is usually made of copper, nickel, etc. The outermost layer of the electrode body 20 does not necessarily have to be an electrode, and may be, for example, a protective tape or a separator.

[0029] The exterior body 40 seals the electrode body 20. The exterior body 40 includes an exterior film 50 and a lid body 60. The exterior film 50 wraps the electrode body 20. In this embodiment, the exterior film 50 is wrapped around the electrode body 20. The lid body 60 is disposed on the side of the electrode body 20 in the FB direction. In another example, the electrode body 20 may be accommodated inside the exterior film 50 configured in a cylindrical shape so that openings 40A are formed at both ends in the FB direction, and the openings 40A may be closed by the lid body 60. In yet another example, the electrode body 20 connected to the lid body 60 may be accommodated inside the exterior film 50 configured in a cylindrical shape so that the openings 40A are formed, and the openings 40A may be closed by the lid body 60.

[0030] From the viewpoint of suitable adhesion to the lid 60, it is preferable that the adhesive film 31 is bonded to the electrode terminal 30. The adhesive film 31 can be selected arbitrarily as long as it is a film capable of bonding the electrode terminal 30 made of metal and the lid 60 made of resin. For example, the adhesive film 31 can be a polyolefin resin such as a polyethylene resin or a polypropylene resin, a cyclic polyolefin resin, or an acid-modified polyolefin resin obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The adhesive film 31 can be a single layer or two or more layers of these films. In this embodiment, the adhesive film 31 is bonded to almost the entire portion of the electrode terminal 30 covered by the lid 60.

[0031] For example, there is a method of forming a storage portion (recess) for storing the electrode body 20 in the exterior film 50 through cold forming. However, it is not necessarily easy to form a deep storage portion by such a method. If an attempt is made to form a deep storage portion (recess) by cold forming (for example, a forming depth of 15 mm), pinholes or cracks will occur in the exterior film 50, which is likely to cause a decrease in battery performance. On the other hand, the exterior body 40 seals the electrode body 20 by wrapping the exterior film 50 around the electrode body 20, so that the electrode body 20 can be easily sealed regardless of the thickness of the electrode body 20. In addition, in order to reduce the dead space between the electrode body 20 and the exterior film 50 to improve the volumetric energy density of the power storage device 10, it is preferable that the exterior film 50 is wrapped so as to contact the outer surface of the electrode body 20. In addition, in an all-solid-state battery, it is necessary to apply a high pressure uniformly from the outer surface of the battery to exhibit battery performance, so it is necessary to eliminate the space between the electrode body 20 and the exterior film 50, and therefore it is preferable that the exterior film 50 is wrapped so as to contact the outer surface of the electrode body 20.

[0032] The exterior film 50 is, for example, a laminate (laminate film) having a base layer 51, a barrier layer 52, and a heat-sealable resin layer 53 in this order. Note that the exterior film 50 does not need to include all of these layers, and for example, the barrier layer 52 may not be included. That is, the exterior film 50 may be made of any material that is flexible and easily bendable, and may be made of, for example, a resin film. Note that the exterior film 50 is preferably heat-sealable.

[0033] The base layer 51 included in the exterior film 50 is a layer for imparting heat resistance to the exterior film 50 and suppressing the occurrence of pinholes that may occur during processing or distribution. The base layer 51 is configured to include at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer. For example, the base layer 51 includes at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer, so that the barrier layer 52 can be protected during processing of the exterior film 50 and breakage of the exterior film 50 can be suppressed. In addition, from the viewpoint of increasing the tensile elongation of the exterior film 50, the stretched polyester resin layer is preferably a biaxially stretched polyester resin layer, and the stretched polyamide resin layer is preferably a biaxially stretched polyamide resin layer. Furthermore, in terms of excellent puncture strength or impact strength, the stretched polyester resin layer is more preferably a biaxially stretched polyethylene terephthalate (PET) film, and the stretched polyamide resin layer is more preferably a biaxially stretched nylon (ONy) film. The base layer 51 may be configured to include both a stretched polyester resin layer and a stretched polyamide resin layer. The thickness of the base layer 51 is, for example, preferably 5 to 300 μm, and more preferably 5 to 150 μm, from the viewpoint of film strength.

[0034] The barrier layer 52 is a layer that at least prevents the intrusion of moisture. The barrier layer 52 is bonded to the base layer 51 via, for example, an adhesive layer 54. Examples of the barrier layer 52 include metal foil, vapor deposition film, and resin layer having barrier properties. Examples of the vapor deposition film include metal vapor deposition film, inorganic oxide vapor deposition film, and carbon-containing inorganic oxide vapor deposition film, and examples of the resin layer include fluorine-containing resins such as polyvinylidene chloride, polymers mainly composed of chlorotrifluoroethylene (CTFE), polymers mainly composed of tetrafluoroethylene (TFE), polymers having fluoroalkyl groups, and polymers mainly composed of fluoroalkyl units, and ethylene-vinyl alcohol copolymers. Examples of the barrier layer 52 include resin films having at least one of these vapor deposition films and resin layers. The barrier layer 52 may be provided in a plurality of layers. It is preferable that the barrier layer 52 includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 52 include aluminum alloys, stainless steel, titanium steel, and steel plates. When used as a metal foil, it is preferable that the material contains at least one of an aluminum alloy foil and a stainless steel foil.

[0035] In the barrier layer 52, the layer made of the above-mentioned metal material may contain recycled metal material. Examples of recycled metal material include recycled aluminum alloy, stainless steel, titanium steel, or steel plate. These recycled materials can be obtained by known methods. The recycled aluminum alloy material can be obtained by the manufacturing method described in International Publication No. 2022 / 092231. The barrier layer 52 may be made of only recycled materials, or may be made of a mixed material of recycled materials and virgin materials. Note that recycled metal materials refer to metal materials that have been made reusable by collecting, isolating, and refining various products used in the city and waste from the manufacturing process. In addition, virgin metal materials refer to new metal materials refined from natural metal resources (raw materials) and are not recycled materials.

[0036] From the viewpoint of improving the formability or conformability of the exterior film 50, the aluminum alloy foil is preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy, and from the viewpoint of further improving the formability, the aluminum alloy foil is preferably an iron-containing aluminum alloy foil. In the iron-containing aluminum alloy foil (100 mass%), the iron content is preferably 0.1 to 9.0 mass%, more preferably 0.5 to 2.0 mass%. By making the iron content 0.1 mass% or more, an exterior film 50 having better formability can be obtained. By making the iron content 9.0 mass% or less, an exterior film 50 having better flexibility can be obtained. Examples of the soft aluminum alloy foil include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Silicon, magnesium, copper, manganese, etc. may be added as necessary. Softening can be performed by annealing treatment, etc. From the viewpoint of improving the mechanical strength of the exterior film 50, it is more preferable that the aluminum alloy foil is a hard aluminum alloy foil composed of, for example, a work-hardened aluminum alloy. Examples of the hard aluminum alloy foil include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-H18, JIS H4160:1994 A8079H-H18, JIS H4000:2014 A8021P-H14, or JIS H4000:2014 A8079P-H14.

[0037] Examples of the stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. From the viewpoint of providing an exterior film 50 with excellent formability, the stainless steel foil is preferably made of austenitic stainless steel.

[0038] Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, and SUS316L, and among these, SUS304 is particularly preferred.

[0039] In the case of a metal foil, the thickness of the barrier layer 52 is sufficient to at least function as a barrier layer that prevents moisture from penetrating, and may be, for example, about 9 to 200 μm. The thickness of the barrier layer 52 is preferably about 85 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, and particularly preferably about 35 μm or less. The thickness of the barrier layer 52 is preferably about 10 μm or more, even more preferably about 20 μm or more, and more preferably about 25 μm or more. The preferred ranges of the thickness of the barrier layer 52 include about 10 to 85 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 52 is made of an aluminum alloy foil, the above-mentioned range is particularly preferable. From the viewpoint of imparting high formability and high rigidity to the exterior film 50, the thickness of the barrier layer 52 is preferably about 35 μm or more, more preferably about 45 μm or more, even more preferably about 50 μm or more, and even more preferably about 55 μm or more, and is preferably about 200 μm or less, more preferably about 85 μm or less, even more preferably about 75 μm or less, and even more preferably about 70 μm or less. The preferable ranges are about 35 to 200 μm, about 35 to 85 μm, about 35 to 75 μm, about 35 to 70 μm, about 45 to 200 μm, about 45 to 85 μm, about 45 to 75 μm, about 45 to 70 μm, about 50 to 200 μm, about 50 to 85 μm, about 50 to 75 μm, about 50 to 70 μm, about 55 to 200 μm, about 55 to 85 μm, about 55 to 75 μm, and about 55 to 70 μm. The exterior film 50 has high formability, which facilitates deep drawing and can contribute to increasing the capacity of the electricity storage device. In addition, since the rigidity of the exterior film 50 is increased, when the exterior film 50 is wrapped around the electrode body 20, the exterior film 50 can be suitably wrapped around the electrode body 20. Furthermore, when the capacity of the electricity storage device is increased, the weight of the electricity storage device increases, but increasing the rigidity of the exterior film 50 can contribute to high sealing performance of the electricity storage device.In particular, when the barrier layer 52 is made of stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less. The thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. Preferred ranges for the thickness of the stainless steel foil include about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

[0040] In addition, when the barrier layer 52 is an aluminum foil, it is preferable that at least the surface opposite to the base layer 51 is provided with a corrosion-resistant film in order to prevent dissolution and corrosion. The barrier layer 52 may be provided with a corrosion-resistant film on both sides. Here, the corrosion-resistant film refers to a thin film that is provided with corrosion resistance (e.g., acid resistance, alkali resistance, etc.) on the barrier layer 52 by performing, for example, hydrothermal conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment such as nickel or chromium, or corrosion prevention treatment by applying a coating agent on the surface of the barrier layer 52. Specifically, the corrosion-resistant film refers to a film that improves the acid resistance of the barrier layer 52 (acid-resistant film), a film that improves the alkali resistance of the barrier layer 52 (alkali-resistant film), etc. The treatment for forming the corrosion-resistant film may be one type, or two or more types may be combined. In addition, not only one layer but also multiple layers may be formed. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the metal foil surface is dissolved by a treatment agent to form a metal compound with excellent corrosion resistance. Note that these treatments may also be included in the definition of chemical conversion treatment. In addition, when the barrier layer 52 has a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer 52.

[0041] The corrosion-resistant coating prevents delamination between the barrier layer 52 (e.g., aluminum alloy foil) and the base layer 51 when the exterior film 50 is formed or wound, prevents dissolution and corrosion of the surface of the barrier layer 52 due to hydrogen fluoride produced by a reaction between an electrolyte and moisture, and in particular prevents dissolution and corrosion of aluminum oxide present on the surface of the barrier layer 52 when the barrier layer 52 is an aluminum alloy foil, and also improves the adhesion (wettability) of the surface of the barrier layer 52, thereby preventing delamination between the base layer 51 and the barrier layer 52 during heat sealing and between the base layer 51 and the barrier layer 52 during forming.

[0042] The heat-sealable resin layer 53 is bonded to the barrier layer 52, for example, via an adhesive layer 55. The heat-sealable resin layer 53 included in the exterior film 50 is a layer that imparts heat-sealing sealability to the exterior film 50. Examples of the heat-sealable resin layer 53 include resin films made of polyester resins such as polyethylene terephthalate resins and polybutylene terephthalate resins, polyolefin resins such as polyethylene resins and polypropylene resins, or acid-modified polyolefin resins obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The thickness of the heat-sealable resin layer 53 is preferably, for example, 20 to 300 μm, and more preferably 40 to 150 μm, in terms of sealability and strength.

[0043] The exterior film 50 preferably has one or more layers having a buffer function (hereinafter referred to as "buffer layer") outside the heat-sealable resin layer 53, more preferably outside the barrier layer 52. The buffer layer may be laminated on the outside of the base material layer 51, or the base material layer 51 may also function as a buffer layer. When the exterior film 50 has multiple buffer layers, the multiple buffer layers may be adjacent to each other, or may be laminated via the base material layer 51, the barrier layer 52, etc.

[0044] The material constituting the buffer layer can be arbitrarily selected from materials having cushioning properties. The material having cushioning properties is, for example, rubber, nonwoven fabric, or foam sheet. The rubber is, for example, natural rubber, fluororubber, or silicone rubber. The rubber hardness is preferably about 20 to 90. The material constituting the nonwoven fabric is preferably a material having excellent heat resistance. When the buffer layer is made of nonwoven fabric, the lower limit of the thickness of the buffer layer is preferably 100 μm, more preferably 200 μm, and more preferably 1000 μm. When the buffer layer is made of nonwoven fabric, the upper limit of the thickness of the buffer layer is preferably 5000 μm, and more preferably 3000 μm. The thickness of the buffer layer is preferably in the range of 100 μm to 5000 μm, 100 μm to 3000 μm, 200 μm to 5000 μm, 200 μm to 3000 μm, 1000 μm to 5000 μm, or 1000 μm to 3000 μm. Among these, the thickness of the buffer layer is most preferably in the range of 1000 μm to 3000 μm.

[0045] When the buffer layer is made of rubber, the lower limit of the buffer layer thickness is preferably 1 mm, more preferably 0.5 mm. When the buffer layer is made of rubber, the upper limit of the buffer layer thickness is preferably 10 mm, more preferably 5 mm, more preferably 2 mm. When the buffer layer is made of rubber, the preferred ranges of the buffer layer thickness are 1 mm to 10 mm, 1 mm to 5 mm, 1 mm to 2 mm, 0.5 mm to 10 mm, 0.5 mm to 5 mm, and 0.5 mm to 2 mm.

[0046] When the exterior film 50 has a buffer layer, the buffer layer functions as a cushion, thereby preventing the exterior film 50 from being damaged by impact when the electricity storage device 10 is dropped or by handling during production of the electricity storage device 10.

[0047] The lid body 60 shown in Fig. 4 has, for example, a rectangular parallelepiped shape, and is, for example, a resin molded product made of a resin material. The lid body 60 may be formed, for example, by cold forming the exterior film 50, or may be a metal molded product. The material constituting the lid body 60 may include at least two or more types of materials selected from a metal oxide, a carbon material, and a rubber material. The material may include a metal oxide, a carbon material, and a rubber material.

[0048] The lid body 60 is preferably made of a resin material. Here, "made of a resin material" means that, when the entire material constituting the lid body 60 is taken as 100% by mass, the content of the resin material is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. In other words, the material constituting the lid body 60 can contain materials other than the resin material in addition to the resin material.

[0049] Specific examples of the resin include thermoplastic resins such as polyester, polyolefin, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenol resin, and modified products of these resins. The resin material may be a mixture of these resins, a copolymer, or a modified product of the copolymer. Among these, the resin material is preferably a heat-sealable resin such as polyester or polyolefin, and more preferably polyolefin. When the resin material is a resin, the lid 60 may be molded by any molding method.

[0050] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyesters. Examples of copolymerized polyesters include copolymerized polyesters in which ethylene terephthalate is the main repeating unit. Specific examples of polyesters include copolymerized polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), and polyethylene (terephthalate / decane dicarboxylate). Of these, the resin material is preferably polybutylene terephthalate from the viewpoint of increasing heat resistance and pressure resistance.

[0051] Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. Among these, polypropylene is preferred as the resin material because it has excellent heat fusion properties and electrolyte resistance.

[0052] The resin as the resin material may contain a filler as necessary. Specific examples of the filler include glass beads, graphite, glass fiber, and carbon fiber. When the resin as the resin material contains the filler, the deformation resistance of the lid body 60 against temperature changes can be improved.

[0053] The melt mass flow rate of the resin material contained in the material constituting the lid body 60 is preferably within the range of 1 g / 10 min to 80 g / 10 min, and more preferably within the range of 5 g / 10 min to 60 g / 10 min. The melt mass flow rate is measured based on JIS K7210-1:2014.

[0054] The lid body 60 may be configured to include a conductive material. "Configured to include a conductive material" means that, when the entire material constituting the lid body 60 is taken as 100% by mass, the content of the conductive material is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. In other words, the material constituting the lid body 60 can contain, in addition to the conductive material, a material other than the conductive material.

[0055] The conductive material constituting the lid body 60 is, for example, a metal material. The metal material constituting the lid body 60 is, for example, aluminum, an aluminum alloy, nickel, copper, or a copper alloy. For example, when the electrode body 20 is a lithium ion battery, the lid body 60 connected to the positive electrode is preferably made of aluminum or an aluminum alloy. The lid body 60 connected to the negative electrode is preferably made of nickel, copper, or a copper alloy. The material constituting the lid body 60 connected to the negative electrode may be copper plated with nickel. The material constituting the lid body 60 may contain recycled metal materials. When the lid body 60 is composed of a conductive material, the lid body 60 also functions as the electrode terminal 30. Since the electrode terminal 30 can be omitted from the electricity storage device 10, the configuration of the electricity storage device 10 can be simplified.

[0056] When the lid 60 is composed of a conductive material, the lid 60 may be bonded to the exterior film 50 via an adhesive film. The adhesive film can be selected arbitrarily as long as it can bond the exterior film 50 and the lid 60. The adhesive film is preferably a laminated film having at least a heat-sealable resin layer, a heat-resistant base material layer, and a heat-sealable resin layer in this order. The specifications of the heat-sealable resin layer of the adhesive film can be the same as those of the heat-sealable resin layer 53. The materials constituting the heat-sealable resin layers on both sides of the adhesive film may be the same or different materials, and are appropriately selected according to the materials constituting the heat-sealable resin layer 53 of the exterior film 50 and the materials constituting the lid 60. The material constituting the heat-sealable resin layer on the side of the adhesive film that is bonded to the lid 60 is preferably an acid-modified polyolefin resin graft-modified with an acid such as maleic anhydride. The heat-sealable resin layer of the adhesive film on the side to be bonded to the exterior film 50 is preferably made of the same material as that constituting the heat-sealable resin layer 53 of the exterior film 50 .

[0057] The heat-resistant base layer may be any film made of a heat-resistant resin, such as a non-stretched or stretched film of polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polymethylpentene (registered trademark), polyacetal cyclic polyolefin, polyethylene, polypropylene, etc. Polyethylene terephthalate is particularly preferred because it is inexpensive and has high strength.

[0058] The adhesive film preferably has adhesiveness. When the adhesive film is disposed between the exterior film 50 and the lid 60 and a second sealing portion 80 is formed as described below, the adhesive film is unlikely to be displaced relative to the lid 60 and the exterior film 50. By incorporating a tackifier resin into the heat-sealable resin layer of the adhesive film, the adhesive film can be given adhesiveness. Examples of the tackifier resin include amorphous polyolefins. Examples of the amorphous polyolefins include amorphous polypropylene and copolymers of amorphous propylene and other α-olefins. The content of the tackifier resin in the base material constituting the heat-sealable resin is preferably 10 to 20% by weight or less.

[0059] The lid 60 has a first surface 61, a second surface 62, and a sealing surface 63. The first surface 61 faces the electrode body 20. The second surface 62 is the surface opposite to the first surface 61. The sealing surface 63 is connected to the first surface 61 and the second surface 62, and is joined to the heat-sealable resin layer 53 of the exterior film 50.

[0060] The seal surface 63 includes a first seal surface 63A, a second seal surface 63B, a third seal surface 63C, and a fourth seal surface 63D. The first seal surface 63A constitutes the upper surface of the lid body 60. The first seal surface 63A extends in a first direction (LR direction in this embodiment) in a front view of the lid body 60. The second seal surface 63B and the third seal surface 63C are connected to the first seal surface 63A and constitute the side surface of the lid body 60. The second seal surface 63B and the third seal surface 63C extend in a second direction (UD direction in this embodiment) intersecting the first direction in a front view of the lid body 60. In this embodiment, the first direction and the second direction are orthogonal to each other in a front view of the lid body 60. The first direction and the second direction do not have to be orthogonal to each other in a front view of the lid body 60. The fourth seal surface 63D constitutes the lower surface of the lid body 60. The fourth sealing surface 63D extends in a first direction (the LR direction in this embodiment) when the lid 60 is viewed from the front.

[0061] When the lid body 60 is plate-shaped, it is preferable that the lid body 60 has a certain degree of thickness so that deformation of the exterior body 40 is suppressed even when the power storage device 10 is arranged in a stacked manner. From another viewpoint, when the lid body 60 is plate-shaped, it is preferable that the sealing surface 63 of the lid body 60 has a certain degree of thickness so that the sealing surface 63 of the lid body 60 and the exterior film 50 can be suitably heat-sealed when forming the second sealing portion 80 described later. The minimum value of the thickness of the lid body 60 is, for example, 1.0 mm, more preferably 3.0 mm, and even more preferably 4.0 mm. The maximum value of the thickness of the lid body 60 is, for example, 20 mm, more preferably 15 mm, and even more preferably 10 mm. The maximum value of the thickness of the lid body 60 may be 20 mm or more. The preferred ranges of the thickness of the material constituting the lid body 60 are 1.0 mm to 20 mm, 1.0 mm to 15 mm, 1.0 mm to 10 mm, 3.0 mm to 20 mm, 3.0 mm to 15 mm, 3.0 mm to 10 mm, 4.0 mm to 20 mm, 4.0 mm to 15 mm, and 4.0 mm to 10 mm. In this embodiment, when the lid body 60 is expressed as a plate-like body, the embodiment in which the lid body 60 is composed only of a film defined by the [packaging terminology] standard of JIS (Japan Industrial Standards) is not included. The thickness of the lid body 60 may vary depending on the part of the lid body 60. When the thickness of the lid body 60 varies depending on the part, the thickness of the lid body 60 is the thickness of the thickest part.

[0062] The cover 60 further includes boundaries 64, 65, 66, and 67. The boundary 64 is a boundary between the first seal surface 63A and the second seal surface 63B. The boundary 65 is a boundary between the first seal surface 63A and the third seal surface 63C. The boundary 66 is a boundary between the fourth seal surface 63D and the second seal surface 63B. The boundary 67 is a boundary between the fourth seal surface 63D and the third seal surface 63C. The boundaries 64 to 67 may have a corner shape, or may be rounded by performing R processing. In this embodiment, the boundaries 64 to 67 are corners.

[0063] From the viewpoint of suitable heat sealing between the lid body 60 and the exterior film 50, it is preferable that the main material of the material constituting the lid body 60 is the same as that of the material constituting the heat-sealable resin layer 53 of the exterior film 50. In this embodiment, examples of the material constituting the lid body 60 include polyester-based resins such as polyethylene terephthalate-based resins and polybutylene terephthalate-based resins, polyolefin-based resins such as polyethylene-based resins, fluorine-based resins, and polypropylene-based resins, cyclic polyolefin-based resins, and acid-modified polyolefin-based resins obtained by graft-modifying these polyolefin-based resins with an acid such as maleic anhydride. From the viewpoint of suitable heat sealing between the lid body 60 and the exterior film 50, it is preferable that the main material of the material constituting the lid body 60 is the same as that of the material constituting the heat-sealable resin layer 53 of the exterior film 50. In this embodiment, the main materials of the material constituting the lid body 60 and the material constituting the heat-sealable resin layer 53 are, for example, polyolefin resins such as polyethylene resins and polypropylene resins, or acid-modified polyolefin resins obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. Note that the main material refers to a material that accounts for 50% or more of the materials contained in the components, for example.

[0064] In this embodiment, the lid body 60 is formed with a through hole 60X into which the electrode terminal 30 is inserted. The through hole 60X penetrates the first surface 61 and the second surface 62. When the electrode body 20 is wrapped in the exterior film 50, the electrode terminal 30 protrudes to the outside of the exterior body 40 through the through hole 60X formed in the lid body 60. A small gap between the through hole 60X of the lid body 60 and the electrode terminal 30 is filled with, for example, resin. In the electricity storage device 10, the position from which the electrode terminal 30 protrudes to the outside can be arbitrarily selected. For example, the electrode terminal 30 may protrude to the outside from a hole formed on any one of the six surfaces of the exterior body 40. In this case, a small gap between the exterior body 40 and the electrode terminal 30 is filled with, for example, resin. In another example, the electrode terminal 30 may protrude to the outside of the exterior body 40 from between the seal surface 63 of the lid body 60 and the exterior film 50. In this case, the through hole 60X may not be formed in the lid body 60. In the electricity storage device 10, the lid body 60 and the electrode terminal 30 are provided as separate bodies, but the lid body 60 and the electrode terminal 30 may be formed integrally. Note that, even when the electrode terminal 30 does not protrude from the edge of the exterior body 40, the lid body 60 may not be formed with the through hole 60X.

[0065] In this embodiment, with the exterior film 50 wrapped around the electrode body 20 so as to have an opening 40A, the facing surfaces of the exterior film 50 (heat-fusible resin layer 53) are heat-sealed to form the first sealing portion 70.

[0066] The first sealed portion 70 is formed by heat-sealing a portion including the first edge 50A and a portion including the second edge 50B of the exterior film 50 shown in FIG. 3. The first sealed portion 70 extends in the longitudinal direction (FB direction) of the exterior body 40. The position at which the first sealed portion 70 is formed in the exterior body 40 can be selected arbitrarily. In this embodiment, the root 70X of the first sealed portion 70 is preferably located on the side 43 at the boundary between the first surface 41 and the second surface 42 of the exterior body 40. The first surface 41 has a larger area than the second surface 42. The root 70X of the first sealed portion 70 may be located on any surface of the exterior body 40. In this embodiment, the first sealed portion 70 protrudes outward from the electrode body 20 in a plan view. The first sealed portion 70 may be folded, for example, toward the second surface 42 of the exterior body 40, or toward the first surface 41.

[0067] When an abnormality occurs in the electrode body 20, gas may be generated inside the exterior body 40. When the electricity storage device 10 is a lithium ion battery, gas such as a volatile organic solvent, carbon monoxide, carbon dioxide, methane, ethane, hydrogen, and hydrogen fluoride may be generated inside the exterior body 40 due to the volatilization of the organic solvent of the electrolyte and the decomposition of the electrolyte. When the electricity storage device 10 is a capacitor, gas may be generated inside the exterior body 40 due to a chemical reaction in the capacitor. When the electricity storage device 10 is an all-solid-state battery, the electrode body 20 may include a solid electrolyte that may generate gas. For example, when the solid electrolyte is a sulfide-based material, hydrogen sulfide gas may be generated. When gas is generated inside the exterior body 40, the internal pressure of the exterior body 40 increases. For this reason, it is necessary to discharge the gas generated inside the exterior body 40 to the outside of the exterior body 40.

[0068] Furthermore, in the manufacturing process of the electricity storage device 10, it is preferable to carry out a step of aging the electricity storage device 10 in a temporarily sealed state in a predetermined temperature environment for a predetermined time period in order to, for example, allow the electrolyte to permeate the electrode body 20 (hereinafter referred to as an "aging step"). In the aging step, gas is generated from the electrode body 20, and it is therefore necessary to discharge the generated gas to the outside of the exterior body 40.

[0069] From this perspective, in this embodiment, the electricity storage device 10 includes a check valve 90 so that gas generated inside the exterior body 40 can be discharged to the outside of the exterior body 40. As the check valve 90, a known valve-type check valve that allows repeated gas release can be used, such as a ball spring type, a poppet type, a duckbill type, an umbrella type, or a diaphragm type. In this embodiment, the check valve 90 is attached to the first sealing portion 70.

[0070] 5 is a front view of the check valve 90 of this embodiment. The check valve 90 includes a housing 91, a valve mechanism 92, and an attachment portion 93. The housing 91 is made of, for example, metal or resin. The housing 91 is, for example, cylindrical, and accommodates the valve mechanism 92 therein. An outlet 91A for discharging gas is formed on the end face of the housing 91 opposite the attachment portion 93. When the check valve 90 is disposed in the first sealing portion 70, the housing 91 is located outside the first sealing portion 70. The housing 91 may be joined to the exterior film 50 by any means, for example.

[0071] The valve mechanism 92 has a spring, a valve body, and a valve seat. That is, in this embodiment, the check valve 90 is a ball-spring type check valve.

[0072] The attachment portion 93 is connected to the housing 91. The attachment portion 93 is made of metal or resin. The attachment portion 93 may be integral with the housing 91, or may be formed separately from the housing 91 and joined to the housing 91. The attachment portion 93 is sandwiched between the mutually facing surfaces (thermally adhesive resin layer 53) of the parts of the exterior film 50 that form the first sealing portion 70. When the attachment portion 93 is made of metal, it is preferable that the attachment portion 93 and the exterior film 50 are joined via an adhesive film that is suitably adhered to both metal and resin. The attachment portion 93 has, for example, a cylindrical shape. From the viewpoint of suitably joining the attachment portion 93 and the exterior film 50, it is preferable that the outer diameter of the attachment portion 93 is smaller than the outer diameter of the housing 91.

[0073] An inlet 93A facing the inside of the exterior body 40 is formed on the end face of the attachment part 93 opposite to the housing 91. When gas is generated inside the exterior body 40 and the internal pressure of the exterior body 40 becomes equal to or higher than the valve opening pressure of the valve mechanism 92, the valve mechanism 92 opens. When the valve mechanism 92 opens, the gas passes through the inlet 93A, the inside of the attachment part 93, the inside of the housing 91, and the outlet 91A in that order, and is discharged to the outside.

[0074] In this embodiment, the second sealed portion 80 is formed by heat-sealing the heat-sealable resin layer 53 of the exterior film 50 and the seal surface 63 of the lid body 60. Hereinafter, the seal strength between the heat-sealable resin layer 53 of the exterior film 50 and the seal surface 63 of the lid body 60 may be referred to as the seal strength of the second sealed portion 80. The seal strength of the second sealed portion 80 is the seal strength between the heat-sealable resin layer 53 and the lid body 60 at the long side portion of the seal surface 63, i.e., the seal surface 63 extending in the LR direction (see FIG. 1A).

[0075] The seal strength of the second sealing portion 80 is measured as follows. First, a cut is made in a portion of the exterior film 50 that constitutes the first surface 41 of the exterior body 40, and three belt-shaped members 41X, 41Y, and 41Z (see the two-dot chain line in FIG. 1B) arranged in the LR direction are formed. In the second and subsequent embodiments and modified examples described below, the belt-shaped members 41X, 41Y, and 41Z are formed so as to avoid the check valve and the opening valve. The width of the three belt-shaped members 41X, 41Y, and 41Z in the LR direction is 15 mm. The ends of the belt-shaped members 41X, 41Y, and 41Z are joined to the lid body 60 at the second sealing portion 80. The length of the lid body 60 in the LR direction is 45 mm or more. Next, the end of the belt-shaped members 41X, 41Y, and 41Z opposite to the end joined to the lid body 60 is pulled upward in the UD direction (the direction opposite to the first surface 41B), thereby measuring the seal strength of each of the belt-shaped members 41X, 41Y, and 41Z. In this embodiment, the seal strength of the second sealing portion 80 is the average value of the seal strengths of the belt-shaped members 41X, 41Y, and 41Z. When the length of the lid body 60 in the LR direction is less than 45 mm, three belt-shaped members of an arbitrary width X mm that is less than 15 mm are formed, and the seal strengths of the three belt-shaped members are measured in the same manner as when the length of the lid body 60 in the LR direction is 45 mm or more. The obtained seal strengths are each divided by the arbitrary width X mm and multiplied by 15 to convert them into the seal strengths of the three belt-shaped members in a width of 15 mm. The seal strength of the second sealing portion 80 is the average value of the seal strengths of the three belt-shaped members converted into a width of 15 mm. When the lid 60 is divided into a plurality of parts including long and short sides, the seal strength of the second sealing portion 80 is the seal strength at the long side portions of the sealing surfaces 63 of the plurality of parts.

[0076] From the viewpoint of suitably maintaining the state in which the electrode body 20 is sealed by the exterior body 40, the seal strength of the second sealing portion 80 is preferably 40N / 15mm or more, more preferably 50N / 15mm or more, more preferably 60N / 15mm or more, more preferably 70N / 15mm or more, and more preferably 85N / 15mm or more. When the seal strength of the second sealing portion 80 is 40N / 15mm or more, the state in which the electrode body 20 is sealed by the exterior body 40 is suitably maintained even if the electricity storage device 10 is used for, for example, several years (less than 10 years). When the seal strength of the second sealing portion 80 is 85N / 15mm or more, the state in which the electrode body 20 is sealed by the exterior body 40 is suitably maintained even if the electricity storage device 10 is used for, for example, 10 years or more. The seal strength of the second sealing portion 80 is preferably 300N / 15mm or less. A preferred range of the seal strength of the second sealing portion 80 is 40N / 15mm to 300N / 15mm, 50N / 15mm to 300N / 15mm, 60N / 15mm to 300N / 15mm, 70N / 15mm to 300N / 15mm, or 85N / 15mm to 300N / 15mm.

[0077] <1-2. Method for manufacturing electricity storage device> 6 is a flowchart showing an example of a method for manufacturing the electricity storage device 10. The method for manufacturing the electricity storage device 10 includes, for example, a first step, a second step, a third step, a fourth step, a fifth step, a sixth step, a seventh step, and an eighth step. The first step to the eighth step are performed, for example, by a manufacturing apparatus for the electricity storage device 10. Note that the first step to the eighth step are merely names of the steps in the method for manufacturing the electricity storage device 10 specified for convenience, and do not necessarily refer to the order of the steps.

[0078] In a first step of step S11, the manufacturing equipment joins the lid body 60 and the electrode terminal 30. By completing the second step, a pair of lid units 60Z in which the electrode terminal 30 is joined to the lid body 60 is completed.

[0079] The second step of step S12 is performed after the first step. In the second step, the manufacturing apparatus places a pair of lid units 60Z on the sides of the electrode body 20, and joins the electrode terminal 30 and the electrode body 20. Note that the manufacturing method for the electricity storage device 10 may include, instead of the first and second steps, a step of first joining the electrode body 20 and the electrode terminal 30, and then joining the lid body 60 to the electrode terminal 30 joined to the electrode body 20.

[0080] The third step of step S13 is performed after the second step. In the third step, the manufacturing device winds the exterior film 50 around the electrode body 20 and the lid body 60. In the third step, the manufacturing device winds the exterior film 50 around the electrode body 20 and the lid body 60 while tension is applied to the exterior film 50, while restricting the movement of the electrode body 20 and the lid body 60 by the restricting means. The restricting means is, for example, a groove into which the electrode body 20 and the lid body 60 are fitted. The restricting means may be a device that applies an external force to the electrode body 20 and the lid body 60 so that the electrode body 20 and the lid body 60 do not move. The restricting means may be a device that applies a force to the electrode body 20 and the lid body 60 in the opposite direction to the direction in which the exterior film 50 is pulled. The restricting means may include a roller that runs on the exterior film 50 while the exterior film 50 is being pulled in order to remove wrinkles in the exterior film 50.

[0081] The fourth step of step S14 is performed after the third step. In the third step, the manufacturing apparatus arranges a check valve 90 in a portion of the exterior film 50 where the first sealed portion 70 is to be formed.

[0082] The fifth step of step S15 is performed after the fourth step. In the fifth step, the manufacturing equipment forms a first sealed portion (hereinafter referred to as a "temporary first sealed portion") having an unsealed portion for injecting an electrolyte solution. In the temporary first sealed portion, the heat-sealable resin layers 53 of the exterior film 50 facing each other and the mounting portion 93 of the check valve 90 are joined. Note that, when the power storage device 10 is, for example, an all-solid-state battery, the step of injecting an electrolyte solution is not necessary, and therefore, in the fifth step, the manufacturing equipment forms the first sealed portion 70 in which the check valve 90 is disposed.

[0083] The sixth step of step S16 is performed after the fifth step. In the sixth step, the manufacturing apparatus forms the second sealed portion 80 by heat-sealing the heat-fusible resin layer 53 of the exterior film 50 and the sealing surface 63 of the lid body 60.

[0084] The seventh step of step S17 is performed after the sixth step. In the seventh step, the manufacturing equipment injects an electrolyte solution through the unsealed portion formed in the temporary first sealed portion.

[0085] The eighth step of step S18 is performed after the seventh step is completed. In the eighth step, the manufacturing apparatus forms the first sealed portion 70 by heat-sealing a portion including an unsealed portion of the temporary first sealed portion. If the check valve 90 is not arranged in the fifth step, the check valve 90 may be arranged in the first sealed portion 70 in the eighth step. Note that, if the power storage device 10 is, for example, an all-solid-state battery, the seventh and eighth steps are omitted. After the eighth step, an aging step is performed. Gas generated in the aging step is discharged to the outside through the check valve 90.

[0086] <1-3. Effects of electricity storage devices> Since the electricity storage device 10 includes the check valve 90, gas generated inside the exterior body 40 can be discharged to the outside.

[0087] Furthermore, when manufacturing an electricity storage device that does not have a check valve (hereinafter referred to as a "virtual electricity storage device"), it is necessary to form a gas pocket to store the gas generated in the aging process. The gas pocket includes the temporary first sealing portion 70 as well as an extended portion of the exterior film 50. The portion of the exterior film 50 that extends beyond the first sealing portion 70 is cut off after the aging process is completed. For this reason, the virtual electricity storage device requires an exterior film 50 that is larger in size than the exterior film 50 provided in the finished virtual electricity storage device.

[0088] On the other hand, in the electricity storage device 10, since the check valve 90 is disposed in the fourth step, the gas generated in the aging step is discharged through the check valve 90. Therefore, in the electricity storage device 10, it is not necessary to form a gas pocket for storing the gas generated in the aging step. In the electricity storage device 10, a small portion of the exterior film 50 is discarded, and therefore the manufacturing cost can be reduced.

[0089] Furthermore, in the hypothetical electricity storage device, a part of the part corresponding to the root 70X of the first sealed portion 70 is heat-sealed to form a gas pocket. After the aging process is completed, a part of the root 70X that was heat-sealed when the gas pocket was formed is heat-sealed again to form the first sealed portion 70. In this way, in the hypothetical electricity storage device, a part of the root 70X is heat-sealed multiple times, so that the strength of the root 70X is reduced. For this reason, for example, when the first sealed portion 70 is folded toward the first surface 41 or the second surface 42, the root 70X of the first sealed portion 70 may be damaged, causing leakage of the electrolyte or the like.

[0090] On the other hand, since the electricity storage device 10 can discharge gas by the check valve 90, the unsealed portion of the temporary first sealed portion formed in the fifth step only needs to be large enough to inject the electrolyte. Therefore, the area that is heat-sealed when forming the first sealed portion 70 in the eighth step may be a small area including the unsealed portion of the temporary first sealed portion. Since the area of ​​the first sealed portion 70 that is heat-sealed multiple times is small in the electricity storage device 10, the strength of the base 70X of the first sealed portion 70 is unlikely to decrease. Therefore, even when the first sealed portion 70 is folded toward the first surface 41 or the second surface 42, the electricity storage device 10 can suppress damage to the base 70X.

[0091] Furthermore, since the gas pocket is mobile, there is a risk that a portion including the base may be damaged due to material fatigue or when an external force such as bending or pulling is applied. The base of the gas pocket coincides with the base 70X of the first sealing portion 70. As described above, the electricity storage device 10 can discharge gas by the check valve 90, so there is no need to form a gas pocket during manufacturing. This makes it possible to prevent the base 70X of the first sealing portion 70 from being damaged.

[0092] [2. Second embodiment] The electricity storage device 200 of the second embodiment differs from the electricity storage device 10 of the first embodiment in the location where the check valve 90 is arranged, but the other configurations are similar to those of the electricity storage device 10 of the first embodiment. The electricity storage device 200 of the second embodiment will be described below, focusing on the parts that differ from the electricity storage device 10 of the first embodiment.

[0093] <2-1. Configuration of the power storage device> Fig. 7 is a perspective view that diagrammatically illustrates an electricity accumulation device 200 according to the second embodiment. Fig. 8 is a cross-sectional view taken along line D8-D8 in Fig. 7.

[0094] In the electricity storage device 200, the check valve 90 is attached to the lid body 60. The check valve 90 and the lid body 60 constitute a lid unit 260Z. The lid unit 260Z is manufactured, for example, by injection molding a material constituting the lid body 60 onto the check valve 90 arranged in a mold, that is, by insert molding. In another example, a hole is formed in the lid body 60, and the mounting portion 93 of the check valve 90 is inserted into the hole.

[0095] In this embodiment, at least a part of the mounting portion 93 of the check valve 90 is embedded inside the lid body 60. At least a part of the housing 91 may be embedded inside the lid body 60. The position of the inlet 93A of the mounting portion 93 can be selected arbitrarily. The inlet 93A may be located on the first surface 61 of the lid body 60, may be located closer to the electrode body 20 than the first surface 61 of the lid body 60, or may be located inside the lid body 60. From the viewpoint of suppressing interference between the check valve 90 and the electrode body 20, it is preferable that the inlet 93A is as far away from the electrode body 20 as possible. In the example shown in FIG. 8, the inlet 93A is located on the first surface 61 of the lid body 60.

[0096] In the electricity storage device 200, the check valve 90 may be attached to one cover body 60 and the other cover body 60. In this case, the opening pressure of the check valve 90 attached to one cover body 60 is preferably lower than the opening pressure of the check valve 90 attached to the other cover body 60. Gas generated inside the exterior body 40 is discharged from the check valve 90 attached to one cover body 60 before the check valve 90 attached to the other cover body 60. For this reason, the location from which the gas is discharged can be limited.

[0097] In another example, in the electricity storage device 200, the check valve 90 may be attached to only one of the lid bodies 60 and the other lid body 60. In other words, the check valve 90 is not attached to the other lid body 60. In this case, the location where the gas is discharged can be limited.

[0098] <2-2. Effects of electricity storage devices> According to the power storage device 200, the same effects as those of the power storage device 10 of the first embodiment can be obtained.

[0099] [3. Third embodiment] The electricity storage device 300 of the third embodiment differs from the electricity storage device 10 of the first embodiment in that it includes a first sealing portion 370 and in the location where the check valve 90 is disposed, but the other configurations are similar to those of the electricity storage device 10 of the first embodiment. The electricity storage device 300 of the third embodiment will be described below, focusing on the parts that differ from the electricity storage device 10 of the first embodiment.

[0100] <3-1. Configuration of the power storage device> Fig. 9 is a perspective view that illustrates a schematic diagram of an electricity storage device 300 according to a third embodiment. Fig. 10 is a cross-sectional view that illustrates an example of a layer structure of an exterior film 50 that the electricity storage device 10 includes.

[0101] The electricity storage device 300 includes a first sealed portion 370. The first sealed portion 370 is a portion that is sealed by joining the outermost layer and the innermost layer of the exterior film 50 in a state where it is wrapped around the electrode body 20.

[0102] As shown in FIG. 10, in this embodiment, the exterior film 50 preferably has a heat-sealable resin layer 56 laminated on the substrate layer 51 opposite to the barrier layer 52. The heat-sealable resin layer 56 is bonded to the substrate layer 51 via, for example, an adhesive layer 57. In the example shown in FIG. 10, the outermost layer of the exterior film 50 is the heat-sealable resin layer 56, and the innermost layer is the heat-sealable resin layer 53, so that the first sealing portion 370 can be suitably formed. Even when the outermost layer of the exterior film 50 is the heat-sealable resin layer 56 and the innermost layer is the heat-sealable resin layer 53, the heat-sealable resin layer 53 and the heat-sealable resin layer 56 may be bonded to each other with an adhesive or the like. When the exterior film 50 has the layer structure shown in FIG. 2, the outermost layer of the exterior film 50 is the substrate layer 51, and the innermost layer is the heat-sealable resin layer 53. Therefore, when the exterior film 50 has the layer structure shown in Fig. 2, the outermost layer and the innermost layer may be joined by, for example, an adhesive. In the example shown in Fig. 10, at least the base material layer 51 may be omitted.

[0103] The position of the second edge 50B of the exterior film 50 can be selected arbitrarily when the exterior film 50 is wrapped around the electrode body 20. The second edge 50B may be located on the first surface 41 of the exterior body 40, may be located on the second surface 42, or may be located on the side 43 at the boundary between the first surface 41 and the second surface 42.

[0104] In this embodiment, the check valve 90 is disposed in the first sealing portion 370. The attachment portion 93 of the check valve 90 is joined to the exterior film 50 in a state where it is sandwiched between the outermost layer and the innermost layer of the exterior film 50.

[0105] <3-2. Effects of power storage devices> Since the electricity storage device 300 includes the check valve 90, gas generated inside the exterior body 40 can be discharged to the outside.

[0106] Since there is no need to form gas pockets during manufacturing of the electricity storage device 300, the formation of portions with low strength in the exterior body 40 can be suppressed.

[0107] [4. Fourth embodiment] The electricity storage device 400 of the fourth embodiment differs from the electricity storage device 10 of the first embodiment in that it includes opening valves 491, 492, but other configurations are similar to those of the electricity storage device 10 of the first embodiment. The electricity storage device 400 of the fourth embodiment will be described below, focusing on the differences from the electricity storage device 10 of the first embodiment.

[0108] <4-1. Configuration of the power storage device> FIG. 11 is a perspective view that shows a schematic diagram of an electricity storage device 400 of a fourth embodiment. The electricity storage device 400 includes opening valves 491 and 492. The opening valves 491 and 492 are films that release gas by peeling or cohesively breaking when gas is generated inside the exterior body 40 and the internal pressure of the exterior body 40 rises. The material constituting the opening valves 491 and 492 can be selected arbitrarily as long as it can function as an opening valve. For example, the material exemplified for the adhesive film 31 can be used as the material constituting the opening valves 491 and 492. The material constituting the opening valves 491 and 492 preferably includes at least one resin layer having a melting peak temperature 5° C. or more lower than the heat-sealable resin layer 53 of the exterior film 50. The adhesive film preferably includes at least one resin layer having a melting peak temperature of 100° C. or more and 135° C. or less.

[0109] The opening valves 491 and 492 are arranged at any positions of the exterior body 40 where gas generated inside the interior of the exterior body 40 can be discharged. In this embodiment, the opening valve 491 is arranged in the first sealing portion 70. The opening valve 492 is arranged in the second sealing portion 80. One of the opening valve 491 and the opening valve 492 may be omitted.

[0110] The opening valve 491 is joined to the opposing heat-sealable resin layers 53 of the exterior film 50. When the internal pressure of the exterior body 40 increases, the opening valve 491 peels off from at least one of the opposing heat-sealable resin layers 53, forming an opening in the first sealed portion 70. Gas generated inside the exterior body 40 passes through the opening formed in the first sealed portion 70 and is discharged to the outside.

[0111] The opening valve 492 is disposed between the heat-sealing resin layer 53 of the exterior film 50 and the seal surface 63 of the lid body 60, in other words, in the second sealing portion 80. The opening valve 492 is joined to the heat-sealing resin layer 53 of the exterior film 50 and the seal surface 63 of the lid body 60. When the internal pressure of the exterior body 40 increases, the opening valve 492 peels off from at least one of the heat-sealing resin layer 53 and the seal surface 63 of the lid body 60, and an opening is formed in the second sealing portion 80. Gas generated inside the exterior body 40 passes through the opening formed in the second sealing portion 80 and is discharged to the outside. The opening valve 492 and the lid body 60 constitute a lid unit 460Z. The manufacturing method of the electricity storage device 400 of the fourth embodiment preferably includes a step of forming a gas pocket that stores the gas generated by the aging step. When a check valve 90 is disposed in the first sealing portion 70, the second sealing portion 80, or the lid body 60 of the electricity storage device 400, the step of forming a gas pocket is not necessary in the manufacturing method for the electricity storage device 400 of the fourth embodiment.

[0112] In the electricity storage device 400, the opening valve 492 may be disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 and the second sealing portion 80 corresponding to the other lid body 60. In this case, the opening pressure of the opening valve 492 disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 is preferably lower than the opening pressure of the opening valve 492 disposed in the second sealing portion 80 corresponding to the other lid body 60. The gas generated inside the exterior body 40 is discharged from the opening valve 492 disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 before the opening valve 492 disposed in the second sealing portion 80 corresponding to the other lid body 60. For this reason, the location from which the gas is discharged can be limited. In addition, even if gas continues to be generated inside the exterior body 40 after the opening valve 492 disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 is peeled off, the gas can be discharged by peeling off the opening valve 492 disposed in the second sealing portion 80 corresponding to the other lid body 60.

[0113] The opening pressure of the opening valve 492 is defined as follows. A virtual electricity storage device 10 is prepared in which the electrode body 20 and the other lid body 60 are omitted from the electricity storage device 400. An air supply jig is attached to any one of the pair of first surfaces 41 and the pair of second surfaces 42 of the virtual electricity storage device. A fixing jig is placed on the pair of first surfaces 41 and the pair of second surfaces 42 of the virtual electricity storage device in a state in which the air supply jig is attached, and the virtual electricity storage device is fixed. Air is supplied from the air supply jig to the inside of the exterior body. The pressure when the opening valve 492 arranged in the second sealing portion 80 corresponding to one of the lid bodies 60 is peeled off and the gas is discharged is the opening pressure of the opening valve 492. Note that, when the virtual electricity storage device 400 includes a check valve and an opening valve other than the opening valve 492, the opening pressure is measured in a state in which the valves other than the opening valve 492, which is the object of measurement of the opening pressure, are closed. The opening pressure of the opening valve 492 arranged in the second sealing portion 80 corresponding to the other lid body 60 can be determined in a similar manner using a virtual electricity storage device 10 in which the electrode body 20 and one of the lid bodies 60 are omitted from the electricity storage device 400.

[0114] In another example, in the electricity storage device 200, the opening valve 492 may be disposed only in the second sealing portion 80 corresponding to one of the lid bodies 60 of the second sealing portion 80. In other words, the opening valve 492 is not disposed in the second sealing portion 80 corresponding to the other lid body 60. In this case, the location where the gas is discharged can be limited.

[0115] <4-2. Effects of electricity storage devices> Since the electricity storage device 400 includes the opening valves 491, 492, for example, when gas is generated inside the exterior body 40 due to an abnormality occurring in the electrode body 20, the gas can be discharged to the outside.

[0116] [5. Modifications] The above-mentioned embodiments are examples of forms that the electricity storage device and the lid unit according to the present invention can take, and are not intended to limit the forms. The electricity storage device and the lid unit according to the present invention can take forms different from those exemplified in the embodiments. One example is a form in which a part of the configuration of each embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to each embodiment. Below, some examples of modified versions of each embodiment are shown. The following modified versions can be combined with each other as long as they are not technically inconsistent.

[0117] <5-1> In the first embodiment, the check valve 90 may be a non-permeable gas-venting film that is permeable to gas but not permeable to moisture. The non-permeable gas-venting film may be composed of a laminate including at least a base layer and an adhesive layer. The non-permeable gas-venting film preferably has a water vapor transmission rate of 10 cc / m or less when left to stand for 48 hours in an environment of 60°C and 90% RH. 2 / day or less, preferably 5cc / m 2 / day or less, more preferably 2cc / m 2 / day or less, more preferably 0cc / m 2 The water vapor transmission rate of the non-water-permeable gas-venting film is measured as follows.

[0118] <Water vapor permeability> The water vapor transmission rate is measured in an environment of 60℃ 90%RH in accordance with the cup method of JIS Z 0208. The test piece is cut into a 75mmφ sample, and three 5mmφ holes are drilled 5mm inside from the outer circumference and set in a jig using a screw-tightening method. A cup with a transmission area of ​​60mmφ is used.

[0119] In order to achieve a good performance, the non-water-permeable gas-exhausting film preferably has a carbon dioxide permeability of 5000 cm 3 / (m 2 ·24h·atm) or higher, preferably 8000cm 3 / (m 2 24h atm) or higher, and more preferably 10,000 cm3 / (m 2 The upper limit of the carbon dioxide permeability of the non-water-permeable gas-permeable film 1 of the present disclosure is, for example, 100,000 cm 3 / (m 2 The carbon dioxide permeability of a non-permeable gas-exhausting film is measured as follows.

[0120] <Carbon dioxide permeability> The carbon dioxide permeability of the film is measured under the following conditions in accordance with the test items specified in JIS K 7126-1:2006: gas permeability and gas permeability coefficient (differential pressure method). Detector: Gas chromatograph (thermal conductivity detector (TDC)) Gas: Carbon dioxide (CO2) (humidified atmosphere) Temperature and humidity: 60±2℃ 50±5%RH Differential pressure: 1 atm (partial pressure at 60℃ and 50% RH (gas: 68.52 cmHg, water vapor: 7.48 cmHg) Transmission area: 15.2×10 -4 m 2 (Transmission part diameter φ4.4×10 -2 m) Number of tests: n=1 Measurement device: Differential pressure gas / vapor transmission rate measurement device

[0121] In order to achieve the desired performance, the non-permeable gas-permeable film preferably has an oxygen permeability of 50 cm 3 / (m 2 ·24h·atm) or more, preferably 100cm 3 / (m 2 ·24h·atm) or more, more preferably 200cm 3 / (m 2 The upper limit of the oxygen permeability of the non-water-permeable gas-releasing film of the present disclosure is, for example, 100,000 cm 3 / (m 2 The oxygen transmission rate of the non-water-permeable gas-releasing film 1 is measured as follows.

[0122] <Oxygen permeability> The oxygen permeability can be measured using an oxygen gas permeability measuring device under conditions of a temperature of 40°C and a humidity of 90% RH in accordance with JIS K7126-2:2006 (Plastics - Films and sheets - Gas permeability test methods - Part 2: isobaric method, Appendix A: Test method for oxygen gas permeability using an electrolytic sensor method). As the oxygen gas permeability measuring device, for example, an OXTRAN2 / 22 manufactured by MOCON, USA, can be used. For the measurement, the non-permeable gas-exhausting film is placed in the above device so that the surface of the film is in contact with oxygen gas, and a permeation area of ​​50 cm is measured. 2 The above measurement is performed under the following conditions. The above measurement is performed in the following manner. First, a carrier gas is supplied into the above device at a flow rate of 10 cc / min for 60 minutes or more to purge the device. The above carrier gas can be nitrogen gas containing about 5% hydrogen. After purging, a test gas is passed through the device, and after 12 hours have elapsed since the start of the flow until the device reaches equilibrium, the measurement is started under the above temperature and humidity conditions. The above test gas is dry oxygen containing at least 99.5% (volume) oxygen. At least three samples are measured under one condition, and the average of the measured values ​​is taken as the oxygen permeability value under that condition. For example, polyolefin resin is a resin with low water vapor permeability and high carbon dioxide permeability, and is suitable as a resin constituting the non-water-permeable gas-venting film of this modified example.

[0123] <5-2> In the first embodiment, a hole may be formed at any position in the exterior film 50, and the check valve 90 may be disposed in the hole. This can be similarly applied to the electricity storage device 200 of the second embodiment, the electricity storage device 300 of the third embodiment, and the electricity storage device 400 of the fourth embodiment.

[0124] <5-3> In the first embodiment, the configuration of the power storage device 10 can be arbitrarily modified. The power storage device 10 may include at least one of the opening valve 491 and the opening valve 492 included in the power storage device 400 of the fourth embodiment. This modification can be similarly applied to the power storage device 200 of the second embodiment and the power storage device 300 of the third embodiment.

[0125] <5-4> In the first embodiment, the configuration of the lid body 60 can be changed arbitrarily. FIG. 12 is a cross-sectional view of the electric storage device 10 according to a modification of the first embodiment. As shown in FIG. 12, the lid body 60 may include a lid main body 60A and a covering body 60B. In this modification, for example, the lid main body 60A is preferably configured to include a conductive material. The covering body 60B covers a part of the lid main body 60A. The covering body 60B is preferably configured to include a resin material. In this modification, the sealing surface 63 of the lid body 60 is formed on the covering body 60B. In order to prevent a gap from being formed between the exterior film 50 and the lid body 60, the covering body 60B preferably has a protruding portion 68 protruding from the sealing surface 63. The protruding portion 68 may be omitted. The protruding portion 68 may be formed integrally with a portion constituting the sealing surface 63 of the covering body 60B, or may be formed separately from the portion constituting the sealing surface 63 of the covering body 60B and joined to the portion constituting the sealing surface 63 of the covering body 60B. The protrusion 68 is preferably formed at a location on the seal surface 63 where the root 70X of the first sealing portion 70 is located. In the example shown in FIG. 12, the root 70X of the first sealing portion 70 is located at the boundary 64 of the lid body 60. For this reason, the protrusion 68 is preferably formed at the boundary 64 on the seal surface 63. The first sealing portion 70 is sealed with the protrusion 68 sandwiched between them. This modification can be similarly applied to the electricity storage device 200 of the second embodiment, the electricity storage device 300 of the third embodiment, and the electricity storage device 400 of the fourth embodiment.

[0126] <5-5> In the second embodiment, the location of the check valve 90 can be changed arbitrarily. Fig. 13 is a front view of an electricity accumulation device 200X according to a modified example of the second embodiment. Fig. 14 is a front view of the lid 60 of Fig. 13.

[0127] As shown in FIG. 13, in the electricity storage device 200X, the check valve 90 may be disposed in the second sealing portion 80. At least a part of the check valve 90 is sandwiched between the heat-sealable resin layer 53 of the exterior film 50 and the sealing surface 63 of the lid body 60. From the viewpoint of enhancing the sealing performance of the second sealing portion 80, as shown in FIG. 13, it is preferable that a recess 69 is formed in the sealing surface 63 of the lid body 60 in which an arbitrary part of the check valve 90 facing the sealing surface 63 is disposed. In this modification, the check valve 90 may be a non-permeable gas venting film. An opening valve 492 may be disposed in the recess 69.

[0128] When the check valve 90 is disposed in the second sealing portion 80, the check valve 90 may be disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 and the second sealing portion 80 corresponding to the other lid body 60. In this case, the opening pressure of the check valve 90 disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 is preferably lower than the opening pressure of the check valve 90 disposed in the second sealing portion 80 corresponding to the other lid body 60. The gas generated inside the exterior body 40 is discharged from the check valve 90 disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 before the check valve 90 disposed in the second sealing portion 80 corresponding to the other lid body 60. For this reason, the location where the gas is discharged can be limited.

[0129] In another example, in the electricity storage device 200, the check valve 90 may be disposed only in the second sealing portion 80 that corresponds to one of the lid bodies 60 of the second sealing portion 80. In other words, the check valve 90 is not disposed in the second sealing portion 80 that corresponds to the other lid body 60. In this case, the location from which the gas is discharged can be limited.

[0130] <5-6> In the second embodiment, the configuration of the lid 60 can be changed arbitrarily. Fig. 15 is a front view of an electricity accumulation device 200Y according to another modified example of the second embodiment. Fig. 16 is a front view of the lid 260 of Fig. 15.

[0131] As shown in Fig. 15, the power storage device 200Y includes a lid body 260. The power storage device 200Y may include at least one of a check valve 90 and an opening valve 492. The lid body 260 is configured by a plurality of divided parts. In the example shown in Fig. 15, the lid body 260 includes a first part 261 and a second part 262. The lid body 260 may be divided into three or more parts.

[0132] The first part 261 and the second part 262 preferably have recesses 261A, 262A formed therein in which the electrode terminal 30 is disposed. When the electricity storage device 200Y includes a check valve 90, the check valve 90 is sandwiched between the first part 261 and the second part 262. The first part 261 and the second part 262 preferably have recesses 261B, 262B formed therein in which any portion of the check valve 90 that faces the first part 261 and the second part 262 is disposed.

[0133] When the power storage device 200Y includes the opening valve 492, the opening valve 492 may be attached between the first part 261 and the second part 262 of the lid body 260. The opening valve 492 may be attached to one of the lid bodies 260 and the other of the lid bodies 260. In this case, the opening pressure of the opening valve 492 attached to one of the lid bodies 260 is preferably lower than the opening pressure of the opening valve 492 attached to the other of the lid bodies 260. The gas generated inside the exterior body 40 is discharged from the opening valve 492 attached to one of the lid bodies 260 before the opening valve 492 attached to the other of the lid bodies 260. For this reason, the location from which the gas is discharged can be limited. In addition, even if gas continues to be generated inside the exterior body 40 after the opening valve 492 attached to one of the lid bodies 260 is peeled off, the opening valve 492 attached to the other of the lid bodies 260 is peeled off, so that the gas can be discharged.

[0134] In another example, in the power storage device 200Y, the opening valve 492 may be attached to only one of the lid bodies 260 and the other lid body 260. In other words, the opening valve 492 is not attached to the other lid body 260. In this case, the location where the gas is discharged can be limited. Note that the opening valve 492 may be attached between the lid main body 60A and the cover body 60B as shown in FIG. 12.

[0135] <5-7> In the third embodiment, a check valve 90 may be disposed in at least one of the second sealing portion 80 and the lid body 60. In this modification, the check valve 90 disposed in the first sealing portion 70 may be omitted. In the third embodiment, opening valves 491, 492 may be disposed in at least one of the first sealing portion 70 and the second sealing portion 80.

[0136] <5-8> In the fourth embodiment, the location where the opening valve 492 is arranged can be changed arbitrarily. For example, as shown in FIG. 17, when the electrode terminal 30 is arranged between the exterior film 50 and the seal surface 63 of the lid body 60, the opening valve 492 may be arranged between the electrode terminal 30 and the exterior film 50. The opening valve 492 is joined to the electrode terminal 30 and the exterior film 50. When the internal pressure of the exterior body 40 increases, the opening valve 492 peels off from at least one of the heat-sealable resin layer 53 of the exterior film 50 and the electrode terminal 30, and an opening is formed in the second sealing portion 80. Gas generated inside the exterior body 40 passes through the opening formed in the second sealing portion 80 and is discharged to the outside.

[0137] <5-9> In the fourth embodiment, the check valve 90 may be disposed in at least one of the first sealing portion 70, the second sealing portion 80, and the lid body 60. When the electricity storage device 400 includes the check valve 90 and at least one of the opening valves 491 and 492, the opening pressure of the check valve 90 is preferably lower than the opening pressures of the opening valves 491 and 492. In this modification, when the increase in the internal pressure of the exterior body 40 is within an expected normal range, gas can be discharged by the check valve 90, and when the increase in the internal pressure of the exterior body 40 is within an abnormal range, gas can be discharged by the opening valves 491 and 492.

[0138] <5-10> In the fourth embodiment, the configuration of the first sealed portion 70 can be changed as desired as long as it is closed by the exterior film 50. As shown in FIG. 18, the first sealed portion 70 may be a portion in which the inner faces of the exterior film 50 are joined together with a first edge 50A and a second edge 50B of the exterior film 50 butted against each other. The inner faces of the exterior film 50 may be joined together by, for example, a front-back tape or an adhesive. In this modification, it is preferable that the first sealed portion 70 is folded toward the first surface 41. This modification can be similarly applied to the first to third embodiments.

[0139] <5-11> In the first embodiment, the exterior film 50 of the electricity storage device 10 may protrude outward from at least one of the two lid bodies 60 in the FB direction. The electrode body 20 is sealed by closing the portion of the exterior film 50 that protrudes outward from the lid body 60. The portion of the exterior film 50 that protrudes outward from the lid body 60 may be folded like a Gabeltop pouch or a brick pouch. In this modification, the length of the electrode terminal in the FB direction is preferably such that it is exposed from the portion of the exterior film 50 that protrudes outward from the lid body 60. This modification can be similarly applied to the second to fourth embodiments.

[0140] <5-12> In the first embodiment, the exterior body 40 may not have one of the two lid bodies 60. In this modification, in the FB direction, in a portion of the exterior body 40 where the lid body 60 is omitted, the electrode body 20 is sealed by closing a portion of the exterior film 50 that protrudes outward beyond the electrode body 20. The portion of the exterior film 50 that protrudes outward beyond the electrode body 20 may be folded like a Gabeltop pouch or a brick pouch. This modification can be similarly applied to the second to fourth embodiments.

[0141] <5-13> In the first embodiment, the outer shape of the exterior body 40 can be changed as desired. The outer shape of the exterior body 40 may be a cylinder, a prism, or a cube. This modification can be similarly applied to the second to fourth embodiments. [Explanation of symbols]

[0142] 10, 200, 200X, 200Y, 300, 400: Energy storage devices 20: Electrode body 40: Exterior body 40A: Opening 50: Exterior film 53: Heat-sealable resin layer (innermost layer) 56: Heat-fusible resin layer (outermost layer) 60: Lid 69: Recess 70, 370: First sealing part 90: Check valve 60Z: 260Z, 460Z: Lid unit 491, 492: Opening valve

Claims

1. An electrode body; An electric storage device comprising: an exterior body that seals the electrode body, The exterior body is An exterior film that wraps the electrode body; a lid that seals the electrode assembly together with the exterior film; a second sealing portion in which the lid body and the exterior film are joined together, The power storage device is At least one of a check valve and an opening valve is disposed in the second sealing portion, The cover has a recess formed on a side surface thereof, At least one of the check valve and the opening valve is disposed in the recess. Energy storage device.

2. An electrode body; An electric storage device comprising: an exterior body that seals the electrode body, The exterior body is An exterior film that wraps the electrode body; a lid that seals the electrode assembly together with the exterior film; a second sealing portion in which the lid body and the exterior film are joined together, The power storage device is a check valve disposed in the second sealing portion; The exterior body includes at least two of the lid bodies, The opening pressure of the check valve arranged in the second sealing portion corresponding to one of the lids is lower than the opening pressure of the check valve arranged in the second sealing portion corresponding to the other lid. Energy storage device.

3. An electrode body; An electric storage device comprising: an exterior body that seals the electrode body, The exterior body is An exterior film that wraps the electrode body; a lid that seals the electrode assembly together with the exterior film; a second sealing portion in which the lid body and the exterior film are joined together, The power storage device is An opening valve is provided at the second sealing portion, The exterior body includes at least two of the lid bodies, The opening pressure of the opening valve arranged in the second sealing portion corresponding to one of the lid bodies is lower than the opening pressure of the opening valve arranged in the second sealing portion corresponding to the other lid body. Energy storage device.

4. The exterior body includes at least two of the lid bodies, At least one of the check valve and the opening valve is disposed in the second sealing portion corresponding to one of the lid bodies, The second sealing portion corresponding to the other lid body is not provided with the check valve and the opening valve. The power storage device according to claim 1 .

5. An electrode body; An electric storage device comprising: an exterior body that seals the electrode body, The exterior body is An exterior film that wraps the electrode body; a lid that seals the electrode body together with the exterior film, The power storage device is An opening valve is attached to the lid body, The lid body includes a plurality of elements, The opening valve is sandwiched between the elements. Energy storage device.

6. The exterior body includes at least two of the lid bodies, The opening pressure of the opening valve attached to one of the lids is lower than the opening pressure of the opening valve attached to the other lid. The electricity storage device according to claim 5 .

7. The exterior body includes at least two of the lid bodies, The opening valve is attached to one of the lids, The other lid body is not provided with the opening valve. The electricity storage device according to claim 5 .

8. A lid body used as an exterior body that seals the electrode body; At least one of a check valve and an opening valve attached to the lid body, A recess is formed on the side surface of the lid body in which at least one of the check valve and the opening valve is disposed. Lid unit.

Images